Fabrication of Conductive Domain Walls in x-cut Congruent Thin-film Lithium Niobate Using an Electrical-field Poling Technique(Invited)

Conductive ferroelectric domain walls have attracted increasing research interest in the field of nanoelectronics,and the fabrication technique for such domain walls is vital.In this study,we investigated in detail the fabrication of conductive domain walls in x-cut congruent thin-film lithium niobate(TFLN)using an electrical-field poling technique.The ferroelectric domain structures can be controlled through the applied electrical field and applied pulse numbers,and the domain inversion process is related to the conduction characteristics of the domain walls.The domain structures in TFLN are revealed using confocal second-harmonic microscopy and piezoresponse force microscopy.The results provide further directions for the development and application of conductive domain walls in TFLN.

High piezoelectricity after field cooling AC poling in temperature stable ternary single crystals manufactured by continuous-feeding Bridgman method

After field cooling(FC)alternating current poling(ACP),we investigated the dielectric and piezoelectric properties of[001]_(pc)-oriented 0.24Pb(In_(1/2)Nb_(1/2))O_(3)(PIN)-0.46Pb(Mg_(1/3)Nb_(2/3))O_(3)(PMN)-0.30PbTiO3(PT)(PIMN-0.30PT)single crystals(SCs),which were manufactured by continuous-feeding Bridgman(CF BM)within morphotropic phase boundary(MPB)region.By ACP with 4 kVrms/cm from 100 to 70℃,the PIMN-0.30PT SC attained high dielectric permittivity of 8330,piezoelectric coefficient(d_(33))of 2750 pC/N,bar mode electromechanical coupling factorκ_(33)of 0.96 with higher phase change temperature(T_(pc))of 103℃,and high Curie temperature(7c)of 180℃.These values are the highest ever reported as PIMN-xPT SC system with Tpc>100℃.The enhancement of these properties is attributed to the induced low symmetry multi-phase supported by phase analysis.This work indicates that FC ACP is a smart and promising method to enhance piezoelectric properties of relaxor-PT ferroelectric SCs including PIMN-xPT,and provides a route to a wide range of piezoelectric device applications.

Pulsed field magnetization of multiple bulks used as field pole of a high-temperature superconducting rotating machine

An array of three GdBa_(2)Cu_(3)O_(7‐δ)bulk high‐temperature superconductors(HTS)that mimic the field pole of a high‐power superconducting motor had been magnetized by pulsed field magnetization(PFM)while cooled by liquid nitrogen.The bulk array was magnetized by a passive PFM technique using three vortex‐type coils placed over each individual bulk and connected in series.The trapped magnetic flux density distribution was comparable to the distribution obtained with more traditional quasi‐static magnetization such as field‐cooling.This suggests that the use of PFM technique on arrays of HTS bulks is possible.PFM has also been performed using each coil individually,to magnetize each bulk sequentially.The magnetization sequences showed a maximum reduction of the peak trapped magnetic flux density of 12%due to the demagnetization effect of the magnetization sequence,while the trapped magnetization distribution was improved.

Ultrahigh energy harvesting properties in Ag decorated potassium-sodium niobite particle-polymer composite

Composite-type piezoelectric nanogenerator(PENG)can potentially provide power to the flexible electronics devices by harvesting the mechanical energy.The electricity output of the PENG is not entirely excavated until now because the polarization dipoles are not sufficiently aligned during the high-voltage poling process.In this study,some Ag particles are attached on the(K_(0.4425)Na_(0.52)Li_(0.0375))(Nb_(0.86)Ta_(0.06)Sb_(0.08))O_(3)(KNN)piezoelectric particles and then they are mixed with multi-walled carbon nanotubes and polydimethylsiloxane to fabricate the PENG device.The Ag particles can reduce the optimal poling electric field from 10 kV/mm down to 5 kV/mm.The PENG device with Ag particles poled at 5 kV/mm can generate the highest open-circuit voltage of 282 V,short-circuit voltage of 32.2 mA,and maximum instantaneous power of 3.5mW under the external mechanical stress of 10 kPa without timedependent degradation(only 27.9 V and 2.6 mA for the pure KNN-based PENG poled at 10 kV/mm).These are much better than previously reported composite-type PENG.The electrical energy generated from the PENG(20mm×40 mm)can light up 40 white light emitting diodes instantaneously without any storage unit during the stomping stage.